Carney, whose new film Sing Street is out now, has scrambled to apologise to not only Keira but her friends and fans.

His troubles don't end there, however.

As well as negative coverage in the press and social media, Carney also came under fire from fellow directors and producers in Hollywood.

Mark Romanek, who directed Keira in 2010's Never Let Me Go, called Carney an "arrogant s***head."

He said working with the actress was: "Utterly spectacular on every level."

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Keira Knightley and John Carney with THAT apology

Joy Gorman produced Keira's 2012 film Seeking a Friend for the End of the World.

She said: "She (Keira) was an absolute dream. Professional, prepared, kind and lovely."

In an industry where reputations and contacts are everything, Carney has been forced to try and rebuild bridges and clarify that Keira's involvement in Begin Again had in no way been detrimental to the film.

He said: "Keira was nothing but professional and dedicated during that film and she contributed hugely to its success."